docs: def extract_mean_std_curves(dstore, what):
      """
      Yield imls/IMT and poes/IMT containg mean and stddev for all sites
      """
      getter = getters.PmapGetter(dstore)
      arr = getter.get_mean().array
      for imt in getter.imtls:
          yield 'imls/' + imt, getter.imtls[imt]
          yield 'poes/' + imt, arr[:, getter.imtls(imt)]